Table 11-Effect of Buffering Eisenia Extract on Carrageenan-Induced Rat Paw Edema Mean Edema, Treatmenta m m 3 t SE ( 6 ) b Saline 1174 5 99 BufferedC Eisenia extract 678 t 1 7 6 d UAdministered intraperitoneally 1 hr before carrageenan. bNumber of animals. C Buffered at pH 7.4 with 0.2 M KH,P0,-Na2P0,. d p < 0.05. multiple-range finding test. Comparison of the anti-inflammatory activity data utilized the Student two-tailed t test (7).
RESULTS AND DISCUSSION
The results of testing the activity of the Eisenia extract for ability to stabilize lysosomal membranes are presented in Table . They have been corrected for any direct inhibition of the enzyme. Acid phosphatase was a poor indicator of lysosomal membrane condition, since the powerful stabilizing agent phenylbutazone, which was used as a positive control, inhibited enzyme release by only 7%. However, phenylbutazone (0.309 mg/ml) and the extract a t a concentration of either 3.087 or 0.309 mg/ml offered significant inhibition of release of 0-glucuronidase. At the lower extract concentration of 0.031 mg/ml, there was no protection.
Since some compounds have been shown to be anti-inflammatory because of their irritant properties (81, it was important to determine if the compound might be acting as an anti-inflammatory agent by virtue of its acidity; it normally was injected a t pH 4.5. When the material was buffered at pH 7.4 and anti-inflammatory activity was assessed (Table ) using the carrageenan-induced rat paw edema model, there was only 42% inhibition of inflammation. This value is somewhat lower than the expected 88% (l), indicating that the protection afforded by the Eisenia extract is due in part to a nonspecific counterirritancy.
It appears that there are two mechanisms for the anti-inflammatory activity of the complex polymer isolated from E. bicyclis (Kjellman) Setchell. One is its ability to stabilize the membranes of lysosomes and inhibit the release of the destructive lysosomal enzymes, and the other is a counterirritancy effect.